Method of kolling upset blanks



April 27, 1954 R. A. M DONALD 2,676,390 METHOD OF ROLLING UPSET BLANKS 7 Filed Feb. 21, 1951 INVEN TOR K0d'erz'cA.MacfiomZd Patented Apr. 27 1954 UNITED "STATES ATENT OFFICE.

signor t Burndy Engineering Company, Inc., a corporation of New York Application February 21, 1951, Serial No. 212,1?!)

1 Claim. Cl. 29-148) This invention relates to the manufacture of electrical connectors and more particularly to the manufacture of bifurcated connectors of the type disclosed in the Dibner Patent Re. 20,096, granted September 8, 1936.

Such connectors consist of a U-bolt, a nut and a follower mounted in the bore of the nut. The wires or cables to be connected are clamped between the under side of the head or bridge of the bolt at the inner end of the bifurcation by screwing the nut on the bolt and causing the follower to engage the other side of the wires.

As disclosed in the concurrently filed application of Marvin Lee and Christian V. Pellier, Serial No. 212,149, entitled Bifurcated Bolt and Method of Manufacture, such device can be made by upsetting a rod of uniform cross-section to form a blank with an intermediate portion of greater diameter than the end portions, which blank is then swedged into a substantially flat form prior to bending into a u-shape.

It has been found that in swedging the blank into the flat form, the material is so Work-hardened that cracking develops during the subsequent bending operation. It is therefore a primary object of my invention to provide a method of manufacture for permitting the bending of the upset piece of rod, without cracking the intermediate portion of the blank.

I accomplish these and other objects and obtain my new results as will be apparent from the device described in the followingspecification, particularly pointed out in the claim, and illustrated in the accompanying drawing, in which Fig. 1 is a perspective view of a piece of rod used for making the blank;

Fig. 2 is a perspective view upsetting;

Fig. 3 is a similar view after rolling a declivity around the intermediate portion;

Figs. 4 and 5 are front and side elevations of the final blank obtained by swedging the rolled blank of Fig. 3;

Fig. 6 is the final article obtained from the blank after bending, threading and assembly.

Referring to the drawing, in Fig. 1, I have shown a piece of rod it] which has been cut to the proper length for the manufacture of the bifurcated bolt of a desired size. In the first operation this rod is upset in a suitable apparatus, such as a header, to provide an intermediate portion I2 of increased diameter and end portions or legs I4 of substantially the same diameter as the stock It. The foregoing procedure results in a substantial redistribution of the metal to permit of the same after cation of Lee and Pellier.

forming the head of the bolt from the enlarged upset portion, the original rod size furnishing the proper amount of metal for the legs, all of which is shown in the aforementioned copending appli- After the upset rod has assumed the shape shown in Fig. 2 of the drawing, the surface of the portion I2 is rolled to produce the peripheral declivity It shown in Fig. 3 of the drawing, which I have found will facilitate the bending operation of forming the bolt and eliminate the cracking of the head or intermediate portion which sometimes occursduring the bending.

The end portions M which form the legs may be rolled or slightly extruded after the upset operation to obtain a better control of the necessary dimensions.

The upset and rolled blank of Fig. 3 is, thereafter, submitted to a swedging operation to form the final blank shown in Figs. 4 and 5. Such blank is described in complete detail in the Lee and Pellier application. As shown, the surfaces 13 of the two legs are connected by a slightly curved portion 20 resulting from the declivity it formed on the intermediate portion l2. The opposite rounded surfaces 22 of the leg portions are connected by a, head or bridge 24. In the fiattening operation the declivity I6 is retained on the side of the head which forms the top of the bolt providing two ribs 26, one on each side of the declivity, now designated as the concave portion 28. On opposite sides of the ribs between the head or bridge and the legs or shanks the flattening operation provides concave portions 30.

After each cold working of the copper alloy used for making electrical connectors, I have found it desirable to anneal the metal by heat which will prevent cracking the metal during later operations.

Following the flattening operation, the blank is bent into U-shape, as shown in Fig. 6, and threads 42 are formed on the two round surfaces 22.

The U-bolt thus formed when made of suitable material may be employed in an electrical connector of the type disclosed in the Dibner patents by assembling it with a nut 44 which is bored and threaded to be received on the threads 52 of the bolt. As is illustrated in Fig. 6, a follower 46 is mounted in the bore of the nut in such manner that it does not become displaced and so that it moves in the slot 38 when the nut is rotated on the bolt. The upper surface 48 of the follower cooperates with the surfaces 46 on the under side of the head of the bolt at the inner end of the slot to clamp conducting wires or cables between the follower and the bolt.

I have thus described my invention, but I desire it understood that it is not confined to the particular forms or uses shown and described, the same being merely illustrative, and that the invention may be carried out in other ways without departing from the spirit of my invention, and, therefore, I claim broadly the right to employ all equivalent instrumentailities coming within the scope of the appended claim, and by means of which, objects of my invention are attained and new results accomplished, as it is obvious that the particular embodiments herein shown and described are only some of the many that can be employed to attain these objects and accomplish these results.

I claim:

The method of forming a blank for use as a bifurcated bolt which comprises the steps of working a piece of metal stock of uniform crosssection by first applying pressure longitudinally to the two end portions thereof causing some of the metal to flow and be re-distributed longitudinally in the metal stock to provide an intermediate portion of greater cross-Se ctional area than the end portions, rolling a peripherally extending declivity on the inter after swedging the rolled 5 form having declivities at tion and bending the piece s termediate portion into a U with parallel eX ing leg end portions.

Number Re. 20,096 168,615 1,446,447 1,668,442 1,674,661 1,665,861 2,120,320 2,133,918 2,289,516 2,362,909 2,573,218 2,614,274

mediate portion, therepiece into a flattened the intermediate poro swedged at the intend- References Cited in the file of this patent Name Date Dibner Sept. 8, 1936 Moore Aug. 80, 1904 Bingham Feb. 27, 1923 Wineman May 1, 1928 Pleister June 26, 1928 I-Iodge April 10, 1938 Wood June 14, 1938 Eccles Oct. 18, 1938 McCullough July 14, 1942 Lind et a1. 1 Nov. 14, 1944 Pavelka Oct. 30, 1951 Moore Oct. 21, 1952 

